1. Field of the Invention
The present invention relates to the communication apparatus, e.g., telephone terminal, fax terminal etc; that connects to a domain name system server (hereafter referred to as DNS server), the server having a ENUM (tElephone Number Mapping) function that stores and manages a telephone number and various destination information corresponding to the telephone number, and provides a user with the information according to a telephone number used for an inquiry by the user (hereafter referred to as inquiry telephone number).
2. Description of Related Art
In recent years of the rapid IP network service development, various researches have been done around the world, on an ENUM function that enables various applications for communication services (e.g., “IP telephones” including e-mail, telephone call, and Internet telephone call; and “IFAX” including fax and Internet fax) utilizing only a currently used telephone number.
A DNS server having the ENUM function is provided with a table that stores and manages a telephone number and destination information including communication service related to the telephone number (e.g. URI (Uniform Resource Identifier) such as e-mail address, ordinary telephone number, IP telephone number, fax number and IFAX number). For example, upon receiving notifications of an inquiry telephone number from a terminal apparatus, destination information corresponding to the inquiry telephone number is obtained from the table so that, out of all obtained destination information, the destination information only related to the apparatus type (service function), which is used by the inquiring terminal apparatus, is provided to the terminal apparatus (cf. non-patent article 1).
In a management table within a DNS server, a telephone number and various destination information corresponding to the telephone number (URI information) is usually registered by an operation setting of the user, under a permission of a person having the telephone number.
For example, when sending an e-mail from a terminal apparatus to a communication destination, the user of the terminal apparatus inputs the destination telephone number in an e-mail destination field of the e-mail application, while maintaining the e-mail application of the terminal apparatus, and executes a transmission command of the e-mail.
The DNS server, upon receiving the telephone number and the transmission command from the terminal apparatus, searches the management table for an e-mail address corresponding to the telephone number and returns the obtained e-mail address of the destination to the terminal apparatus.
Upon receiving the e-mail address of the destination from the DNS server, the user of the terminal apparatus can e-mail the destination using the e-mail address.
According to the DNS server having the above described ENUM function, the user of the terminal apparatus can easily obtain the destination information as long as the user has the destination telephone number, even if the user does not have the complete destination information (such as e-mail address or IFAX number of the destination). [Non-patent article 1] Shigeki GOTO et al., “Internet telephone and ENUM” [on-line], Oct. 18, 2002, Japan Network Information Center, [searched on Nov. 25, 2003], Internet <URL: HYPERLINK http://www.nic.ad.jp/ja/materials/after/20021018/ENUM20021018.PDF>
The above described art has the following shortcomings. When the terminal apparatus, connected to the DNS server having the described ENUM function, transmits a destination telephone number to the DNS server, in ordered to obtain the destination information corresponding to the telephone number (e.g., transmitting to the DNS server the inquiry telephone number using the IFAX service function), the destination information relating to only the IFAX service function is obtained from the DNS server, even if they are a plurality of types of destination information managed in the table. In other words, the user is only notified about the destination information related to a single service function, even though there are other types of destination information available for the inquiry telephone number.
Further, according to the terminal apparatus that is connected to the above described DNS server, even though there are a plurality of types of destination information that correspond to the telephone number, only one type of destination information for one service function can be obtained from the DNS server. Therefore, when other types of communication (using other service functions such as e-mail and IP telephone) are intended to be used during the execution of the current service function (for which an appropriate destination is obtained), the executed communication operation has to be first terminated before another inquiry can be made to the DNS server. Then, the destination information relating to the other service functions (such as IP telephone and e-mail) is separately obtained from the DNS server, making the communication operatability (for other service functions) very inconvenient.